It is known that several hormonal primary messengers are capable of regulating developmentally significant biological responses in embryonic palatal tissue by modulating intracellular levels of cAMP. The effects of cAMP on metabolic pathways in eukaryotes are mediated by cAMP-dependent protein kinases (cAMP-dPK) and we have demonstrated spatial and temporal alterations of these enzymes in tissue of the developing mammalian secondary palate. The notion that changes in the amounts or subcellular compartmentalization of cAMP-dPKs during tissue morphogenesis and subsequent to hormone stimulation is supported by studies in other tissue and forms part of the framework for pursuing the studies outlined in the current application. The characterization of cAMP-dPK in tissue derived from the developing mammalian palate has allowed consideration of cAMP-dPK as a key regulatory enzyme, capable of transducing hormonally elevated intracellular levels of cAMP into metabolic responses during orofacial ontogenesis. Our overall objectives in this application include: 1) identification of endogenous substrates for cAMP-dPK in embryonic palatal tissue, generation of antisera directed against these endogenous substrate proteins and administration of these antisera to pregnant mice in an effort to alter normal craniofacial development, 2) determination of whether the temporal alterations in soluble cAMP-dPK that we have defined as well as responses to hormonal challenge are the result of transcriptional regulation of cAMP-dPK gene expression and/or subcellular compartmentalization of regulatory and catalytic subunits, 3) determination of whether differentiation of palatal epithelial and/or mesenchymal tissue are cAMP-dPK mediated processes utilizing a) isozyme- and site-specific cAMP analogues and b) antisense oligonucleotides to respectively either stimulate or block expression of genes for cAMP-dPK regulatory subunits, and 4) analysis of the effect of a cleft palate teratogen (retinoic acid) on cAMP-dPK activities in developing palatal tissue. These studies address the premise that alterations in cAMP-dPK levels or cellular distribution can be recognized by palatal cells as signals which may regulate the cells metabolic response during orofacial ontogenesis.